/*
   * Core IEEE1394 transaction logic

   *
   * Copyright (C) 2004-2006 Kristian Hoegsberg <krh@bitplanet.net>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software Foundation,
   * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
   */

  #include <linux/bug.h>

  #include <linux/completion.h>

  #include <linux/device.h>
  #include <linux/errno.h>

  #include <linux/firewire.h>

  #include <linux/firewire-constants.h>
  #include <linux/fs.h>
  #include <linux/init.h>

  #include <linux/idr.h>

  #include <linux/jiffies.h>

  #include <linux/kernel.h>

  #include <linux/list.h>

  #include <linux/module.h>

  #include <linux/rculist.h>

  #include <linux/slab.h>
  #include <linux/spinlock.h>
  #include <linux/string.h>
  #include <linux/timer.h>
  #include <linux/types.h>

  #include <linux/workqueue.h>

  
  #include <asm/byteorder.h>

  #include "core.h"

  #define HEADER_PRI(pri)			((pri) << 0)
  #define HEADER_TCODE(tcode)		((tcode) << 4)
  #define HEADER_RETRY(retry)		((retry) << 8)
  #define HEADER_TLABEL(tlabel)		((tlabel) << 10)
  #define HEADER_DESTINATION(destination)	((destination) << 16)
  #define HEADER_SOURCE(source)		((source) << 16)
  #define HEADER_RCODE(rcode)		((rcode) << 12)
  #define HEADER_OFFSET_HIGH(offset_high)	((offset_high) << 0)
  #define HEADER_DATA_LENGTH(length)	((length) << 16)
  #define HEADER_EXTENDED_TCODE(tcode)	((tcode) << 0)
  
  #define HEADER_GET_TCODE(q)		(((q) >> 4) & 0x0f)
  #define HEADER_GET_TLABEL(q)		(((q) >> 10) & 0x3f)
  #define HEADER_GET_RCODE(q)		(((q) >> 12) & 0x0f)
  #define HEADER_GET_DESTINATION(q)	(((q) >> 16) & 0xffff)
  #define HEADER_GET_SOURCE(q)		(((q) >> 16) & 0xffff)
  #define HEADER_GET_OFFSET_HIGH(q)	(((q) >> 0) & 0xffff)
  #define HEADER_GET_DATA_LENGTH(q)	(((q) >> 16) & 0xffff)
  #define HEADER_GET_EXTENDED_TCODE(q)	(((q) >> 0) & 0xffff)

  #define HEADER_DESTINATION_IS_BROADCAST(q) \
  	(((q) & HEADER_DESTINATION(0x3f)) == HEADER_DESTINATION(0x3f))

  #define PHY_PACKET_CONFIG	0x0
  #define PHY_PACKET_LINK_ON	0x1
  #define PHY_PACKET_SELF_ID	0x2

  #define PHY_CONFIG_GAP_COUNT(gap_count)	(((gap_count) << 16) | (1 << 22))
  #define PHY_CONFIG_ROOT_ID(node_id)	((((node_id) & 0x3f) << 24) | (1 << 23))
  #define PHY_IDENTIFIER(id)		((id) << 30)

  /* returns 0 if the split timeout handler is already running */
  static int try_cancel_split_timeout(struct fw_transaction *t)
  {
  	if (t->is_split_transaction)
  		return del_timer(&t->split_timeout_timer);
  	else
  		return 1;
  }

  static int close_transaction(struct fw_transaction *transaction,

  			     struct fw_card *card, int rcode)

  {

  	struct fw_transaction *t;

  	unsigned long flags;
  
  	spin_lock_irqsave(&card->lock, flags);

  	list_for_each_entry(t, &card->transaction_list, link) {
  		if (t == transaction) {

  			if (!try_cancel_split_timeout(t)) {

  				spin_unlock_irqrestore(&card->lock, flags);
  				goto timed_out;
  			}

  			list_del_init(&t->link);

  			card->tlabel_mask &= ~(1ULL << t->tlabel);

  			break;
  		}
  	}

  	spin_unlock_irqrestore(&card->lock, flags);

  	if (&t->link != &card->transaction_list) {

  		t->callback(card, rcode, NULL, 0, t->callback_data);

  		return 0;
  	}

   timed_out:

  	return -ENOENT;

  }

  /*
   * Only valid for transactions that are potentially pending (ie have
   * been sent).
   */

  int fw_cancel_transaction(struct fw_card *card,
  			  struct fw_transaction *transaction)

  {

  	/*
  	 * Cancel the packet transmission if it's still queued.  That

  	 * will call the packet transmission callback which cancels

  	 * the transaction.
  	 */

  
  	if (card->driver->cancel_packet(card, &transaction->packet) == 0)
  		return 0;

  	/*
  	 * If the request packet has already been sent, we need to see
  	 * if the transaction is still pending and remove it in that case.
  	 */

  	return close_transaction(transaction, card, RCODE_CANCELLED);

  }
  EXPORT_SYMBOL(fw_cancel_transaction);

  static void split_transaction_timeout_callback(unsigned long data)
  {
  	struct fw_transaction *t = (struct fw_transaction *)data;
  	struct fw_card *card = t->card;
  	unsigned long flags;
  
  	spin_lock_irqsave(&card->lock, flags);
  	if (list_empty(&t->link)) {
  		spin_unlock_irqrestore(&card->lock, flags);
  		return;
  	}
  	list_del(&t->link);
  	card->tlabel_mask &= ~(1ULL << t->tlabel);
  	spin_unlock_irqrestore(&card->lock, flags);

  	t->callback(card, RCODE_CANCELLED, NULL, 0, t->callback_data);
  }

  static void start_split_transaction_timeout(struct fw_transaction *t,
  					    struct fw_card *card)
  {
  	unsigned long flags;
  
  	spin_lock_irqsave(&card->lock, flags);
  
  	if (list_empty(&t->link) || WARN_ON(t->is_split_transaction)) {
  		spin_unlock_irqrestore(&card->lock, flags);
  		return;
  	}
  
  	t->is_split_transaction = true;
  	mod_timer(&t->split_timeout_timer,
  		  jiffies + card->split_timeout_jiffies);
  
  	spin_unlock_irqrestore(&card->lock, flags);
  }

  static void transmit_complete_callback(struct fw_packet *packet,
  				       struct fw_card *card, int status)

  {
  	struct fw_transaction *t =
  	    container_of(packet, struct fw_transaction, packet);
  
  	switch (status) {
  	case ACK_COMPLETE:

  		close_transaction(t, card, RCODE_COMPLETE);

  		break;
  	case ACK_PENDING:

  		start_split_transaction_timeout(t, card);

  		break;
  	case ACK_BUSY_X:
  	case ACK_BUSY_A:
  	case ACK_BUSY_B:

  		close_transaction(t, card, RCODE_BUSY);

  		break;
  	case ACK_DATA_ERROR:

  		close_transaction(t, card, RCODE_DATA_ERROR);

  		break;

  	case ACK_TYPE_ERROR:

  		close_transaction(t, card, RCODE_TYPE_ERROR);

  		break;
  	default:

  		/*
  		 * In this case the ack is really a juju specific
  		 * rcode, so just forward that to the callback.
  		 */

  		close_transaction(t, card, status);

  		break;
  	}
  }

  static void fw_fill_request(struct fw_packet *packet, int tcode, int tlabel,

  		int destination_id, int source_id, int generation, int speed,

  		unsigned long long offset, void *payload, size_t length)

  {
  	int ext_tcode;

  	if (tcode == TCODE_STREAM_DATA) {
  		packet->header[0] =
  			HEADER_DATA_LENGTH(length) |
  			destination_id |
  			HEADER_TCODE(TCODE_STREAM_DATA);
  		packet->header_length = 4;
  		packet->payload = payload;
  		packet->payload_length = length;
  
  		goto common;
  	}

  	if (tcode > 0x10) {

  		ext_tcode = tcode & ~0x10;

  		tcode = TCODE_LOCK_REQUEST;
  	} else
  		ext_tcode = 0;
  
  	packet->header[0] =

  		HEADER_RETRY(RETRY_X) |
  		HEADER_TLABEL(tlabel) |
  		HEADER_TCODE(tcode) |

  		HEADER_DESTINATION(destination_id);

  	packet->header[1] =

  		HEADER_OFFSET_HIGH(offset >> 32) | HEADER_SOURCE(source_id);

  	packet->header[2] =
  		offset;
  
  	switch (tcode) {
  	case TCODE_WRITE_QUADLET_REQUEST:
  		packet->header[3] = *(u32 *)payload;
  		packet->header_length = 16;
  		packet->payload_length = 0;
  		break;
  
  	case TCODE_LOCK_REQUEST:
  	case TCODE_WRITE_BLOCK_REQUEST:
  		packet->header[3] =

  			HEADER_DATA_LENGTH(length) |
  			HEADER_EXTENDED_TCODE(ext_tcode);

  		packet->header_length = 16;
  		packet->payload = payload;
  		packet->payload_length = length;
  		break;
  
  	case TCODE_READ_QUADLET_REQUEST:
  		packet->header_length = 12;
  		packet->payload_length = 0;
  		break;
  
  	case TCODE_READ_BLOCK_REQUEST:
  		packet->header[3] =

  			HEADER_DATA_LENGTH(length) |
  			HEADER_EXTENDED_TCODE(ext_tcode);

  		packet->header_length = 16;
  		packet->payload_length = 0;
  		break;

  
  	default:

  		WARN(1, "wrong tcode %d
  ", tcode);

  	}

   common:

  	packet->speed = speed;
  	packet->generation = generation;

  	packet->ack = 0;

  	packet->payload_mapped = false;

  }

  static int allocate_tlabel(struct fw_card *card)
  {
  	int tlabel;
  
  	tlabel = card->current_tlabel;
  	while (card->tlabel_mask & (1ULL << tlabel)) {
  		tlabel = (tlabel + 1) & 0x3f;
  		if (tlabel == card->current_tlabel)
  			return -EBUSY;
  	}
  
  	card->current_tlabel = (tlabel + 1) & 0x3f;
  	card->tlabel_mask |= 1ULL << tlabel;
  
  	return tlabel;
  }

  /**

   * fw_send_request() - submit a request packet for transmission
   * @card:		interface to send the request at
   * @t:			transaction instance to which the request belongs
   * @tcode:		transaction code
   * @destination_id:	destination node ID, consisting of bus_ID and phy_ID
   * @generation:		bus generation in which request and response are valid
   * @speed:		transmission speed
   * @offset:		48bit wide offset into destination's address space
   * @payload:		data payload for the request subaction
   * @length:		length of the payload, in bytes
   * @callback:		function to be called when the transaction is completed
   * @callback_data:	data to be passed to the transaction completion callback

   *

   * Submit a request packet into the asynchronous request transmission queue.
   * Can be called from atomic context.  If you prefer a blocking API, use
   * fw_run_transaction() in a context that can sleep.

   *

   * In case of lock requests, specify one of the firewire-core specific %TCODE_
   * constants instead of %TCODE_LOCK_REQUEST in @tcode.

   *

   * Make sure that the value in @destination_id is not older than the one in
   * @generation.  Otherwise the request is in danger to be sent to a wrong node.

   *

   * In case of asynchronous stream packets i.e. %TCODE_STREAM_DATA, the caller

   * needs to synthesize @destination_id with fw_stream_packet_destination_id().

   * It will contain tag, channel, and sy data instead of a node ID then.
   *
   * The payload buffer at @data is going to be DMA-mapped except in case of

   * @length <= 8 or of local (loopback) requests.  Hence make sure that the
   * buffer complies with the restrictions of the streaming DMA mapping API.

   * @payload must not be freed before the @callback is called.
   *
   * In case of request types without payload, @data is NULL and @length is 0.
   *
   * After the transaction is completed successfully or unsuccessfully, the
   * @callback will be called.  Among its parameters is the response code which
   * is either one of the rcodes per IEEE 1394 or, in case of internal errors,

   * the firewire-core specific %RCODE_SEND_ERROR.  The other firewire-core
   * specific rcodes (%RCODE_CANCELLED, %RCODE_BUSY, %RCODE_GENERATION,
   * %RCODE_NO_ACK) denote transaction timeout, busy responder, stale request
   * generation, or missing ACK respectively.

   *
   * Note some timing corner cases:  fw_send_request() may complete much earlier
   * than when the request packet actually hits the wire.  On the other hand,
   * transaction completion and hence execution of @callback may happen even
   * before fw_send_request() returns.

   */

  void fw_send_request(struct fw_card *card, struct fw_transaction *t, int tcode,
  		     int destination_id, int generation, int speed,
  		     unsigned long long offset, void *payload, size_t length,
  		     fw_transaction_callback_t callback, void *callback_data)

  {
  	unsigned long flags;

  	int tlabel;

  	/*

  	 * Allocate tlabel from the bitmap and put the transaction on
  	 * the list while holding the card spinlock.
  	 */

  
  	spin_lock_irqsave(&card->lock, flags);

  	tlabel = allocate_tlabel(card);
  	if (tlabel < 0) {

  		spin_unlock_irqrestore(&card->lock, flags);
  		callback(card, RCODE_SEND_ERROR, NULL, 0, callback_data);
  		return;
  	}

  	t->node_id = destination_id;

  	t->tlabel = tlabel;

  	t->card = card;

  	t->is_split_transaction = false;

  	setup_timer(&t->split_timeout_timer,
  		    split_transaction_timeout_callback, (unsigned long)t);

  	t->callback = callback;
  	t->callback_data = callback_data;

  	fw_fill_request(&t->packet, tcode, t->tlabel,
  			destination_id, card->node_id, generation,
  			speed, offset, payload, length);

  	t->packet.callback = transmit_complete_callback;

  	list_add_tail(&t->link, &card->transaction_list);
  
  	spin_unlock_irqrestore(&card->lock, flags);

  	card->driver->send_request(card, &t->packet);
  }
  EXPORT_SYMBOL(fw_send_request);

  struct transaction_callback_data {
  	struct completion done;
  	void *payload;
  	int rcode;
  };
  
  static void transaction_callback(struct fw_card *card, int rcode,
  				 void *payload, size_t length, void *data)
  {
  	struct transaction_callback_data *d = data;
  
  	if (rcode == RCODE_COMPLETE)
  		memcpy(d->payload, payload, length);
  	d->rcode = rcode;
  	complete(&d->done);
  }
  
  /**

   * fw_run_transaction() - send request and sleep until transaction is completed

   *

   * Returns the RCODE.  See fw_send_request() for parameter documentation.
   * Unlike fw_send_request(), @data points to the payload of the request or/and

   * to the payload of the response.  DMA mapping restrictions apply to outbound
   * request payloads of >= 8 bytes but not to inbound response payloads.

   */
  int fw_run_transaction(struct fw_card *card, int tcode, int destination_id,

  		       int generation, int speed, unsigned long long offset,

  		       void *payload, size_t length)

  {
  	struct transaction_callback_data d;
  	struct fw_transaction t;

  	init_timer_on_stack(&t.split_timeout_timer);

  	init_completion(&d.done);

  	d.payload = payload;

  	fw_send_request(card, &t, tcode, destination_id, generation, speed,

  			offset, payload, length, transaction_callback, &d);

  	wait_for_completion(&d.done);

  	destroy_timer_on_stack(&t.split_timeout_timer);

  
  	return d.rcode;
  }
  EXPORT_SYMBOL(fw_run_transaction);

  static DEFINE_MUTEX(phy_config_mutex);
  static DECLARE_COMPLETION(phy_config_done);

  
  static void transmit_phy_packet_callback(struct fw_packet *packet,
  					 struct fw_card *card, int status)

  {

  	complete(&phy_config_done);

  }

  static struct fw_packet phy_config_packet = {

  	.header_length	= 12,
  	.header[0]	= TCODE_LINK_INTERNAL << 4,

  	.payload_length	= 0,
  	.speed		= SCODE_100,
  	.callback	= transmit_phy_packet_callback,
  };

  void fw_send_phy_config(struct fw_card *card,
  			int node_id, int generation, int gap_count)

  {

  	long timeout = DIV_ROUND_UP(HZ, 10);

  	u32 data = PHY_IDENTIFIER(PHY_PACKET_CONFIG);
  
  	if (node_id != FW_PHY_CONFIG_NO_NODE_ID)
  		data |= PHY_CONFIG_ROOT_ID(node_id);
  
  	if (gap_count == FW_PHY_CONFIG_CURRENT_GAP_COUNT) {
  		gap_count = card->driver->read_phy_reg(card, 1);
  		if (gap_count < 0)
  			return;
  
  		gap_count &= 63;
  		if (gap_count == 63)
  			return;
  	}
  	data |= PHY_CONFIG_GAP_COUNT(gap_count);

  	mutex_lock(&phy_config_mutex);

  	phy_config_packet.header[1] = data;
  	phy_config_packet.header[2] = ~data;

  	phy_config_packet.generation = generation;

  	reinit_completion(&phy_config_done);

  
  	card->driver->send_request(card, &phy_config_packet);
  	wait_for_completion_timeout(&phy_config_done, timeout);

  	mutex_unlock(&phy_config_mutex);

  }

  static struct fw_address_handler *lookup_overlapping_address_handler(
  	struct list_head *list, unsigned long long offset, size_t length)

  {
  	struct fw_address_handler *handler;

  	list_for_each_entry_rcu(handler, list, link) {

  		if (handler->offset < offset + length &&
  		    offset < handler->offset + handler->length)
  			return handler;
  	}
  
  	return NULL;
  }

  static bool is_enclosing_handler(struct fw_address_handler *handler,
  				 unsigned long long offset, size_t length)
  {
  	return handler->offset <= offset &&
  		offset + length <= handler->offset + handler->length;
  }

  static struct fw_address_handler *lookup_enclosing_address_handler(
  	struct list_head *list, unsigned long long offset, size_t length)

  {
  	struct fw_address_handler *handler;

  	list_for_each_entry_rcu(handler, list, link) {

  		if (is_enclosing_handler(handler, offset, length))

  			return handler;
  	}
  
  	return NULL;
  }

  static DEFINE_SPINLOCK(address_handler_list_lock);

  static LIST_HEAD(address_handler_list);

  const struct fw_address_region fw_high_memory_region =

  	{ .start = FW_MAX_PHYSICAL_RANGE, .end = 0xffffe0000000ULL, };

  EXPORT_SYMBOL(fw_high_memory_region);

  static const struct fw_address_region low_memory_region =

  	{ .start = 0x000000000000ULL, .end = FW_MAX_PHYSICAL_RANGE, };

  
  #if 0

  const struct fw_address_region fw_private_region =

  	{ .start = 0xffffe0000000ULL, .end = 0xfffff0000000ULL,  };

  const struct fw_address_region fw_csr_region =

  	{ .start = CSR_REGISTER_BASE,
  	  .end   = CSR_REGISTER_BASE | CSR_CONFIG_ROM_END,  };

  const struct fw_address_region fw_unit_space_region =

  	{ .start = 0xfffff0000900ULL, .end = 0x1000000000000ULL, };

  #endif  /*  0  */

  static bool is_in_fcp_region(u64 offset, size_t length)
  {
  	return offset >= (CSR_REGISTER_BASE | CSR_FCP_COMMAND) &&
  		offset + length <= (CSR_REGISTER_BASE | CSR_FCP_END);
  }

  /**

   * fw_core_add_address_handler() - register for incoming requests
   * @handler:	callback
   * @region:	region in the IEEE 1212 node space address range

   *
   * region->start, ->end, and handler->length have to be quadlet-aligned.
   *
   * When a request is received that falls within the specified address range,
   * the specified callback is invoked.  The parameters passed to the callback
   * give the details of the particular request.

   *

   * To be called in process context.

   * Return value:  0 on success, non-zero otherwise.

   *

   * The start offset of the handler's address region is determined by
   * fw_core_add_address_handler() and is returned in handler->offset.

   *
   * Address allocations are exclusive, except for the FCP registers.

   */

  int fw_core_add_address_handler(struct fw_address_handler *handler,
  				const struct fw_address_region *region)

  {
  	struct fw_address_handler *other;

  	int ret = -EBUSY;

  	if (region->start & 0xffff000000000003ULL ||

  	    region->start >= region->end ||

  	    region->end   > 0x0001000000000000ULL ||

  	    handler->length & 3 ||
  	    handler->length == 0)
  		return -EINVAL;

  	spin_lock(&address_handler_list_lock);

  	handler->offset = region->start;

  	while (handler->offset + handler->length <= region->end) {

  		if (is_in_fcp_region(handler->offset, handler->length))
  			other = NULL;
  		else
  			other = lookup_overlapping_address_handler
  					(&address_handler_list,
  					 handler->offset, handler->length);

  		if (other != NULL) {

  			handler->offset += other->length;

  		} else {

  			list_add_tail_rcu(&handler->link, &address_handler_list);

  			ret = 0;
  			break;
  		}
  	}

  	spin_unlock(&address_handler_list_lock);

  
  	return ret;
  }

  EXPORT_SYMBOL(fw_core_add_address_handler);
  
  /**

   * fw_core_remove_address_handler() - unregister an address handler

   *

   * To be called in process context.
   *

   * When fw_core_remove_address_handler() returns, @handler->callback() is
   * guaranteed to not run on any CPU anymore.

   */

  void fw_core_remove_address_handler(struct fw_address_handler *handler)
  {

  	spin_lock(&address_handler_list_lock);

  	list_del_rcu(&handler->link);

  	spin_unlock(&address_handler_list_lock);

  	synchronize_rcu();

  }

  EXPORT_SYMBOL(fw_core_remove_address_handler);
  
  struct fw_request {
  	struct fw_packet response;

  	u32 request_header[4];

  	int ack;
  	u32 length;
  	u32 data[0];
  };

  static void free_response_callback(struct fw_packet *packet,
  				   struct fw_card *card, int status)

  {
  	struct fw_request *request;
  
  	request = container_of(packet, struct fw_request, response);
  	kfree(request);
  }

  int fw_get_response_length(struct fw_request *r)
  {
  	int tcode, ext_tcode, data_length;
  
  	tcode = HEADER_GET_TCODE(r->request_header[0]);
  
  	switch (tcode) {
  	case TCODE_WRITE_QUADLET_REQUEST:
  	case TCODE_WRITE_BLOCK_REQUEST:
  		return 0;
  
  	case TCODE_READ_QUADLET_REQUEST:
  		return 4;
  
  	case TCODE_READ_BLOCK_REQUEST:
  		data_length = HEADER_GET_DATA_LENGTH(r->request_header[3]);
  		return data_length;
  
  	case TCODE_LOCK_REQUEST:
  		ext_tcode = HEADER_GET_EXTENDED_TCODE(r->request_header[3]);
  		data_length = HEADER_GET_DATA_LENGTH(r->request_header[3]);
  		switch (ext_tcode) {
  		case EXTCODE_FETCH_ADD:
  		case EXTCODE_LITTLE_ADD:
  			return data_length;
  		default:
  			return data_length / 2;
  		}
  
  	default:

  		WARN(1, "wrong tcode %d
  ", tcode);

  		return 0;
  	}
  }

  void fw_fill_response(struct fw_packet *response, u32 *request_header,
  		      int rcode, void *payload, size_t length)

  {
  	int tcode, tlabel, extended_tcode, source, destination;

  	tcode          = HEADER_GET_TCODE(request_header[0]);
  	tlabel         = HEADER_GET_TLABEL(request_header[0]);
  	source         = HEADER_GET_DESTINATION(request_header[0]);
  	destination    = HEADER_GET_SOURCE(request_header[1]);
  	extended_tcode = HEADER_GET_EXTENDED_TCODE(request_header[3]);

  
  	response->header[0] =

  		HEADER_RETRY(RETRY_1) |
  		HEADER_TLABEL(tlabel) |
  		HEADER_DESTINATION(destination);

  	response->header[1] =

  		HEADER_SOURCE(source) |
  		HEADER_RCODE(rcode);

  	response->header[2] = 0;
  
  	switch (tcode) {
  	case TCODE_WRITE_QUADLET_REQUEST:
  	case TCODE_WRITE_BLOCK_REQUEST:

  		response->header[0] |= HEADER_TCODE(TCODE_WRITE_RESPONSE);

  		response->header_length = 12;
  		response->payload_length = 0;
  		break;
  
  	case TCODE_READ_QUADLET_REQUEST:
  		response->header[0] |=

  			HEADER_TCODE(TCODE_READ_QUADLET_RESPONSE);

  		if (payload != NULL)
  			response->header[3] = *(u32 *)payload;
  		else
  			response->header[3] = 0;

  		response->header_length = 16;
  		response->payload_length = 0;
  		break;
  
  	case TCODE_READ_BLOCK_REQUEST:
  	case TCODE_LOCK_REQUEST:

  		response->header[0] |= HEADER_TCODE(tcode + 2);

  		response->header[3] =

  			HEADER_DATA_LENGTH(length) |
  			HEADER_EXTENDED_TCODE(extended_tcode);

  		response->header_length = 16;

  		response->payload = payload;
  		response->payload_length = length;

  		break;
  
  	default:

  		WARN(1, "wrong tcode %d
  ", tcode);

  	}

  	response->payload_mapped = false;

  }

  EXPORT_SYMBOL(fw_fill_response);

  static u32 compute_split_timeout_timestamp(struct fw_card *card,
  					   u32 request_timestamp)
  {
  	unsigned int cycles;
  	u32 timestamp;
  
  	cycles = card->split_timeout_cycles;
  	cycles += request_timestamp & 0x1fff;
  
  	timestamp = request_timestamp & ~0x1fff;
  	timestamp += (cycles / 8000) << 13;
  	timestamp |= cycles % 8000;
  
  	return timestamp;
  }
  
  static struct fw_request *allocate_request(struct fw_card *card,
  					   struct fw_packet *p)

  {
  	struct fw_request *request;
  	u32 *data, length;

  	int request_tcode;

  	request_tcode = HEADER_GET_TCODE(p->header[0]);

  	switch (request_tcode) {
  	case TCODE_WRITE_QUADLET_REQUEST:

  		data = &p->header[3];

  		length = 4;
  		break;
  
  	case TCODE_WRITE_BLOCK_REQUEST:
  	case TCODE_LOCK_REQUEST:

  		data = p->payload;

  		length = HEADER_GET_DATA_LENGTH(p->header[3]);

  		break;
  
  	case TCODE_READ_QUADLET_REQUEST:
  		data = NULL;
  		length = 4;
  		break;
  
  	case TCODE_READ_BLOCK_REQUEST:
  		data = NULL;

  		length = HEADER_GET_DATA_LENGTH(p->header[3]);

  		break;
  
  	default:

  		fw_notice(card, "ERROR - corrupt request received - %08x %08x %08x
  ",

  			 p->header[0], p->header[1], p->header[2]);

  		return NULL;
  	}

  	request = kmalloc(sizeof(*request) + length, GFP_ATOMIC);

  	if (request == NULL)
  		return NULL;

  	request->response.speed = p->speed;

  	request->response.timestamp =
  			compute_split_timeout_timestamp(card, p->timestamp);

  	request->response.generation = p->generation;

  	request->response.ack = 0;

  	request->response.callback = free_response_callback;

  	request->ack = p->ack;

  	request->length = length;

  	if (data)

  		memcpy(request->data, data, length);

  	memcpy(request->request_header, p->header, sizeof(p->header));

  
  	return request;
  }

  void fw_send_response(struct fw_card *card,
  		      struct fw_request *request, int rcode)

  {

  	if (WARN_ONCE(!request, "invalid for FCP address handlers"))
  		return;

  	/* unified transaction or broadcast transaction: don't respond */
  	if (request->ack != ACK_PENDING ||
  	    HEADER_DESTINATION_IS_BROADCAST(request->request_header[0])) {

  		kfree(request);

  		return;

  	}

  	if (rcode == RCODE_COMPLETE)
  		fw_fill_response(&request->response, request->request_header,

  				 rcode, request->data,
  				 fw_get_response_length(request));

  	else
  		fw_fill_response(&request->response, request->request_header,
  				 rcode, NULL, 0);

  
  	card->driver->send_response(card, &request->response);
  }

  EXPORT_SYMBOL(fw_send_response);

  /**
   * fw_get_request_speed() - returns speed at which the @request was received
   */
  int fw_get_request_speed(struct fw_request *request)
  {
  	return request->response.speed;
  }
  EXPORT_SYMBOL(fw_get_request_speed);

  static void handle_exclusive_region_request(struct fw_card *card,
  					    struct fw_packet *p,
  					    struct fw_request *request,
  					    unsigned long long offset)

  {
  	struct fw_address_handler *handler;

  	int tcode, destination, source;

  	destination = HEADER_GET_DESTINATION(p->header[0]);

  	source      = HEADER_GET_SOURCE(p->header[1]);

  	tcode       = HEADER_GET_TCODE(p->header[0]);
  	if (tcode == TCODE_LOCK_REQUEST)
  		tcode = 0x10 + HEADER_GET_EXTENDED_TCODE(p->header[3]);

  	rcu_read_lock();

  	handler = lookup_enclosing_address_handler(&address_handler_list,
  						   offset, request->length);

  	if (handler)

  		handler->address_callback(card, request,
  					  tcode, destination, source,

  					  p->generation, offset,

  					  request->data, request->length,
  					  handler->callback_data);

  	rcu_read_unlock();

  
  	if (!handler)
  		fw_send_response(card, request, RCODE_ADDRESS_ERROR);

  }

  
  static void handle_fcp_region_request(struct fw_card *card,
  				      struct fw_packet *p,
  				      struct fw_request *request,
  				      unsigned long long offset)
  {
  	struct fw_address_handler *handler;

  	int tcode, destination, source;
  
  	if ((offset != (CSR_REGISTER_BASE | CSR_FCP_COMMAND) &&
  	     offset != (CSR_REGISTER_BASE | CSR_FCP_RESPONSE)) ||
  	    request->length > 0x200) {
  		fw_send_response(card, request, RCODE_ADDRESS_ERROR);
  
  		return;
  	}
  
  	tcode       = HEADER_GET_TCODE(p->header[0]);
  	destination = HEADER_GET_DESTINATION(p->header[0]);
  	source      = HEADER_GET_SOURCE(p->header[1]);
  
  	if (tcode != TCODE_WRITE_QUADLET_REQUEST &&
  	    tcode != TCODE_WRITE_BLOCK_REQUEST) {
  		fw_send_response(card, request, RCODE_TYPE_ERROR);
  
  		return;
  	}

  	rcu_read_lock();
  	list_for_each_entry_rcu(handler, &address_handler_list, link) {

  		if (is_enclosing_handler(handler, offset, request->length))
  			handler->address_callback(card, NULL, tcode,
  						  destination, source,

  						  p->generation, offset,
  						  request->data,

  						  request->length,
  						  handler->callback_data);
  	}

  	rcu_read_unlock();

  
  	fw_send_response(card, request, RCODE_COMPLETE);
  }
  
  void fw_core_handle_request(struct fw_card *card, struct fw_packet *p)
  {
  	struct fw_request *request;
  	unsigned long long offset;
  
  	if (p->ack != ACK_PENDING && p->ack != ACK_COMPLETE)
  		return;

  	if (TCODE_IS_LINK_INTERNAL(HEADER_GET_TCODE(p->header[0]))) {
  		fw_cdev_handle_phy_packet(card, p);
  		return;
  	}

  	request = allocate_request(card, p);

  	if (request == NULL) {
  		/* FIXME: send statically allocated busy packet. */
  		return;
  	}
  
  	offset = ((u64)HEADER_GET_OFFSET_HIGH(p->header[1]) << 32) |
  		p->header[2];
  
  	if (!is_in_fcp_region(offset, request->length))
  		handle_exclusive_region_request(card, p, request, offset);
  	else
  		handle_fcp_region_request(card, p, request, offset);
  
  }

  EXPORT_SYMBOL(fw_core_handle_request);

  void fw_core_handle_response(struct fw_card *card, struct fw_packet *p)

  {
  	struct fw_transaction *t;
  	unsigned long flags;
  	u32 *data;
  	size_t data_length;

  	int tcode, tlabel, source, rcode;

  	tcode	= HEADER_GET_TCODE(p->header[0]);
  	tlabel	= HEADER_GET_TLABEL(p->header[0]);
  	source	= HEADER_GET_SOURCE(p->header[1]);
  	rcode	= HEADER_GET_RCODE(p->header[1]);

  
  	spin_lock_irqsave(&card->lock, flags);
  	list_for_each_entry(t, &card->transaction_list, link) {
  		if (t->node_id == source && t->tlabel == tlabel) {

  			if (!try_cancel_split_timeout(t)) {

  				spin_unlock_irqrestore(&card->lock, flags);
  				goto timed_out;
  			}

  			list_del_init(&t->link);

  			card->tlabel_mask &= ~(1ULL << t->tlabel);

  			break;
  		}
  	}
  	spin_unlock_irqrestore(&card->lock, flags);
  
  	if (&t->link == &card->transaction_list) {

   timed_out:

  		fw_notice(card, "unsolicited response (source %x, tlabel %x)
  ",

  			  source, tlabel);

  		return;
  	}

  	/*
  	 * FIXME: sanity check packet, is length correct, does tcodes
  	 * and addresses match.
  	 */

  
  	switch (tcode) {
  	case TCODE_READ_QUADLET_RESPONSE:

  		data = (u32 *) &p->header[3];

  		data_length = 4;
  		break;
  
  	case TCODE_WRITE_RESPONSE:
  		data = NULL;
  		data_length = 0;
  		break;
  
  	case TCODE_READ_BLOCK_RESPONSE:
  	case TCODE_LOCK_RESPONSE:

  		data = p->payload;

  		data_length = HEADER_GET_DATA_LENGTH(p->header[3]);

  		break;
  
  	default:
  		/* Should never happen, this is just to shut up gcc. */
  		data = NULL;
  		data_length = 0;
  		break;
  	}

  	/*
  	 * The response handler may be executed while the request handler
  	 * is still pending.  Cancel the request handler.
  	 */
  	card->driver->cancel_packet(card, &t->packet);

  	t->callback(card, rcode, data, data_length, t->callback_data);
  }

  EXPORT_SYMBOL(fw_core_handle_response);

  /**
   * fw_rcode_string - convert a firewire result code to an error description
   * @rcode: the result code
   */
  const char *fw_rcode_string(int rcode)
  {
  	static const char *const names[] = {
  		[RCODE_COMPLETE]       = "no error",
  		[RCODE_CONFLICT_ERROR] = "conflict error",
  		[RCODE_DATA_ERROR]     = "data error",
  		[RCODE_TYPE_ERROR]     = "type error",
  		[RCODE_ADDRESS_ERROR]  = "address error",
  		[RCODE_SEND_ERROR]     = "send error",
  		[RCODE_CANCELLED]      = "timeout",
  		[RCODE_BUSY]           = "busy",
  		[RCODE_GENERATION]     = "bus reset",
  		[RCODE_NO_ACK]         = "no ack",
  	};
  
  	if ((unsigned int)rcode < ARRAY_SIZE(names) && names[rcode])
  		return names[rcode];
  	else
  		return "unknown";
  }
  EXPORT_SYMBOL(fw_rcode_string);

  static const struct fw_address_region topology_map_region =

  	{ .start = CSR_REGISTER_BASE | CSR_TOPOLOGY_MAP,
  	  .end   = CSR_REGISTER_BASE | CSR_TOPOLOGY_MAP_END, };

  static void handle_topology_map(struct fw_card *card, struct fw_request *request,
  		int tcode, int destination, int source, int generation,

  		unsigned long long offset, void *payload, size_t length,
  		void *callback_data)

  {

  	int start;

  
  	if (!TCODE_IS_READ_REQUEST(tcode)) {
  		fw_send_response(card, request, RCODE_TYPE_ERROR);
  		return;
  	}
  
  	if ((offset & 3) > 0 || (length & 3) > 0) {
  		fw_send_response(card, request, RCODE_ADDRESS_ERROR);
  		return;
  	}
  
  	start = (offset - topology_map_region.start) / 4;

  	memcpy(payload, &card->topology_map[start], length);

  
  	fw_send_response(card, request, RCODE_COMPLETE);
  }
  
  static struct fw_address_handler topology_map = {

  	.length			= 0x400,

  	.address_callback	= handle_topology_map,
  };

  static const struct fw_address_region registers_region =

  	{ .start = CSR_REGISTER_BASE,
  	  .end   = CSR_REGISTER_BASE | CSR_CONFIG_ROM, };

  static void update_split_timeout(struct fw_card *card)
  {
  	unsigned int cycles;
  
  	cycles = card->split_timeout_hi * 8000 + (card->split_timeout_lo >> 19);

  	/* minimum per IEEE 1394, maximum which doesn't overflow OHCI */
  	cycles = clamp(cycles, 800u, 3u * 8000u);

  
  	card->split_timeout_cycles = cycles;
  	card->split_timeout_jiffies = DIV_ROUND_UP(cycles * HZ, 8000);
  }

  static void handle_registers(struct fw_card *card, struct fw_request *request,
  		int tcode, int destination, int source, int generation,

  		unsigned long long offset, void *payload, size_t length,
  		void *callback_data)

  {

  	int reg = offset & ~CSR_REGISTER_BASE;

  	__be32 *data = payload;

  	int rcode = RCODE_COMPLETE;

  	unsigned long flags;

  
  	switch (reg) {

  	case CSR_PRIORITY_BUDGET:
  		if (!card->priority_budget_implemented) {
  			rcode = RCODE_ADDRESS_ERROR;
  			break;
  		}
  		/* else fall through */

  	case CSR_NODE_IDS:

  		/*
  		 * per IEEE 1394-2008 8.3.22.3, not IEEE 1394.1-2004 3.2.8
  		 * and 9.6, but interoperable with IEEE 1394.1-2004 bridges
  		 */

  		/* fall through */
  
  	case CSR_STATE_CLEAR:
  	case CSR_STATE_SET:
  	case CSR_CYCLE_TIME:
  	case CSR_BUS_TIME:
  	case CSR_BUSY_TIMEOUT:

  		if (tcode == TCODE_READ_QUADLET_REQUEST)

  			*data = cpu_to_be32(card->driver->read_csr(card, reg));

  		else if (tcode == TCODE_WRITE_QUADLET_REQUEST)

  			card->driver->write_csr(card, reg, be32_to_cpu(*data));

  		else
  			rcode = RCODE_TYPE_ERROR;
  		break;

  	case CSR_RESET_START:

  		if (tcode == TCODE_WRITE_QUADLET_REQUEST)

  			card->driver->write_csr(card, CSR_STATE_CLEAR,
  						CSR_STATE_BIT_ABDICATE);

  		else

  			rcode = RCODE_TYPE_ERROR;
  		break;

  	case CSR_SPLIT_TIMEOUT_HI:
  		if (tcode == TCODE_READ_QUADLET_REQUEST) {
  			*data = cpu_to_be32(card->split_timeout_hi);
  		} else if (tcode == TCODE_WRITE_QUADLET_REQUEST) {
  			spin_lock_irqsave(&card->lock, flags);
  			card->split_timeout_hi = be32_to_cpu(*data) & 7;
  			update_split_timeout(card);
  			spin_unlock_irqrestore(&card->lock, flags);
  		} else {
  			rcode = RCODE_TYPE_ERROR;
  		}
  		break;
  
  	case CSR_SPLIT_TIMEOUT_LO:
  		if (tcode == TCODE_READ_QUADLET_REQUEST) {
  			*data = cpu_to_be32(card->split_timeout_lo);
  		} else if (tcode == TCODE_WRITE_QUADLET_REQUEST) {
  			spin_lock_irqsave(&card->lock, flags);
  			card->split_timeout_lo =
  					be32_to_cpu(*data) & 0xfff80000;
  			update_split_timeout(card);
  			spin_unlock_irqrestore(&card->lock, flags);
  		} else {
  			rcode = RCODE_TYPE_ERROR;
  		}
  		break;

  	case CSR_MAINT_UTILITY:
  		if (tcode == TCODE_READ_QUADLET_REQUEST)
  			*data = card->maint_utility_register;
  		else if (tcode == TCODE_WRITE_QUADLET_REQUEST)
  			card->maint_utility_register = *data;
  		else
  			rcode = RCODE_TYPE_ERROR;
  		break;

  	case CSR_BROADCAST_CHANNEL:
  		if (tcode == TCODE_READ_QUADLET_REQUEST)
  			*data = cpu_to_be32(card->broadcast_channel);
  		else if (tcode == TCODE_WRITE_QUADLET_REQUEST)
  			card->broadcast_channel =
  			    (be32_to_cpu(*data) & BROADCAST_CHANNEL_VALID) |
  			    BROADCAST_CHANNEL_INITIAL;
  		else
  			rcode = RCODE_TYPE_ERROR;

  		break;
  
  	case CSR_BUS_MANAGER_ID:
  	case CSR_BANDWIDTH_AVAILABLE:
  	case CSR_CHANNELS_AVAILABLE_HI:
  	case CSR_CHANNELS_AVAILABLE_LO:

  		/*
  		 * FIXME: these are handled by the OHCI hardware and

  		 * the stack never sees these request. If we add
  		 * support for a new type of controller that doesn't
  		 * handle this in hardware we need to deal with these

  		 * transactions.
  		 */

  		BUG();
  		break;

  	default:

  		rcode = RCODE_ADDRESS_ERROR;

  		break;
  	}

  
  	fw_send_response(card, request, rcode);

  }
  
  static struct fw_address_handler registers = {
  	.length			= 0x400,
  	.address_callback	= handle_registers,
  };

  static void handle_low_memory(struct fw_card *card, struct fw_request *request,
  		int tcode, int destination, int source, int generation,
  		unsigned long long offset, void *payload, size_t length,
  		void *callback_data)
  {
  	/*
  	 * This catches requests not handled by the physical DMA unit,
  	 * i.e., wrong transaction types or unauthorized source nodes.
  	 */
  	fw_send_response(card, request, RCODE_TYPE_ERROR);
  }
  
  static struct fw_address_handler low_memory = {

  	.length			= FW_MAX_PHYSICAL_RANGE,

  	.address_callback	= handle_low_memory,
  };

  MODULE_AUTHOR("Kristian Hoegsberg <krh@bitplanet.net>");
  MODULE_DESCRIPTION("Core IEEE1394 transaction logic");
  MODULE_LICENSE("GPL");

  static const u32 vendor_textual_descriptor[] = {

  	/* textual descriptor leaf () */

  	0x00060000,

  	0x00000000,
  	0x00000000,
  	0x4c696e75,		/* L i n u */
  	0x78204669,		/* x   F i */
  	0x72657769,		/* r e w i */

  	0x72650000,		/* r e     */

  };

  static const u32 model_textual_descriptor[] = {
  	/* model descriptor leaf () */
  	0x00030000,
  	0x00000000,
  	0x00000000,
  	0x4a756a75,		/* J u j u */
  };
  
  static struct fw_descriptor vendor_id_descriptor = {
  	.length = ARRAY_SIZE(vendor_textual_descriptor),

  	.immediate = 0x03001f11,

  	.key = 0x81000000,

  	.data = vendor_textual_descriptor,
  };
  
  static struct fw_descriptor model_id_descriptor = {
  	.length = ARRAY_SIZE(model_textual_descriptor),

  	.immediate = 0x17023901,

  	.key = 0x81000000,
  	.data = model_textual_descriptor,

  };

  static int __init fw_core_init(void)
  {

  	int ret;

  	fw_workqueue = alloc_workqueue("firewire", WQ_MEM_RECLAIM, 0);

  	if (!fw_workqueue)

  		return -ENOMEM;

  	ret = bus_register(&fw_bus_type);

  	if (ret < 0) {

  		destroy_workqueue(fw_workqueue);

  		return ret;

  	}

  	fw_cdev_major = register_chrdev(0, "firewire", &fw_device_ops);
  	if (fw_cdev_major < 0) {
  		bus_unregister(&fw_bus_type);

  		destroy_workqueue(fw_workqueue);

  		return fw_cdev_major;
  	}

  	fw_core_add_address_handler(&topology_map, &topology_map_region);
  	fw_core_add_address_handler(&registers, &registers_region);

  	fw_core_add_address_handler(&low_memory, &low_memory_region);

  	fw_core_add_descriptor(&vendor_id_descriptor);
  	fw_core_add_descriptor(&model_id_descriptor);

  
  	return 0;
  }
  
  static void __exit fw_core_cleanup(void)
  {

  	unregister_chrdev(fw_cdev_major, "firewire");

  	bus_unregister(&fw_bus_type);

  	destroy_workqueue(fw_workqueue);

  	idr_destroy(&fw_device_idr);

  }
  
  module_init(fw_core_init);
  module_exit(fw_core_cleanup);